@lm219ya I can’t recommend to you Valves for the 845 as I only recently bought a Quad Set of Linlai WE 845’s.
When having purchased the Linlai WE 845’s and then informing the designer builder of my 845 Power Amp’s of what I had done. I was caught out by the reply, as the EE was not understanding the Linlai WE 845, it was not recognised for being a true 845 Valve, he referred to the Linlai WE 845 as a Doppelganger replacement with Specifications that are not meeting an 845 Spec’s.
I have not yet used the Linlai WE 845, due to some additional math investigation being required.
For 300b Tubes more assistance might be forthcoming quite soon, as within my local audio group, there are Three 300b designed Amp’s in use, along with Five Different Brands of 300b Tubes.
An Amp Comparison is soon to occur, where Amp’s will be couped to the variety of available 300b Tubes and other available Driver Tubes, designated to be Tube Rolling Valves. There will be permutations selected for Driver > Power Valves during the comparisons. There might be some info on 300b Valves worth knowing following this session of comparisons.